Ethyl-3-chloro-2-hydroxy-3-butenoate



fcan 'be readilycopolymerized United States Patent 2,865,952 rETHYL-3-CHLOR0-2-HYDROXY-3-BUTENOATE Harry A. Stansbnry, Jr., SouthCharleston, and-Howard R. Guest, Charleston, W. Va., assignors to UnionCarbide Corporation, a corporation of New York No Drawing. ApplicationNovember 12,1954 Serial No. 468,578

1 Claim. ((31.260-484) This invention relates .to certain .novelderivatives of .Zechloro-acrolein .and .more particularly to a group of:novel compounds comprising the nitrile and ethyl ester of -3=chloror2hydroxy 3-butenoic acid, as well as to-amethod of makingthese-compounds.

The compounds of thepresentinvention are characterized by the fact thatthey are tetrafunctional, and thus are 'tcap'able of undergoing manydifferent types of reaction.

The compounds of the present invention can be con- .venientlyipreparedfrom'acrolein. The acrolein is treated with chlorine to form2,3-chloropropionaldhyde according" "to the following equation:

The 2,3-dichloropropionaldehyde thus formed-is then convertedto2-chloroacrolein. Dehydrochlorinat ion of the dichloropropiona'ldehyde--is readily efiected' in the presence of hot water The resulting2-chloroacrolein is treated with hydrogen cyanide to form2-chloroacrolein cyanohydrin which can also be described as the nitrileof 3chloro-2-hydroxy3- butenoic acid.

This compound is unusual in that it contains a reactive double-bond, achlorine group, a hydroxyl group and a cyano group in a small molecule.

It is desirable in carrying out the foregoing reaction that essentiallyanhydrous 2-chloroacrolein be used, since water exerts a strongdissociative elfect on cyanohydrins and the reaction mixture must have alow water content if good yields of the nitrile are to be obtained.

If it is desired to prepare an ester of 3-chloro-2-hydroxy- 3-butenoicacid, conversion of the nitrile to the ester can be effected by treatingthe nitrile with alcoholic hydrochloric acid according to the followingequation:

It will be noted that the nitrile and ethyl ester of 3chloro-Z-hydroxy-3-butenoic acid, whose preparation is outlined above,each contain four different functional cyanohydrin having'the followingproperties: boiling point -at 3mm. absolute-86 Analysis of the productshowed 30.9%

V 60.2% chlorine and 11.9% nitrogen.

efiiciency were 79 percent.

.groups in' a relatively small PatentedDec. 23,, :11958 exceptionallyversatile in their reactions 'Wl th other com .pounds and are 'very'useful intermediates for further "synthesis.

In .order to point out more fully the nature of the ipresent inventionthe 'following specific examples are "given 'ofmethods of making the;nitrile and 'ethylester of 3 chloro 2-hydroxy-3 butenoic acid, aswellas'methods fof:copo1ymerizing the ester withistyre'ne andacrylonitrile.

Example I.Preparati0n of2-chloroacrolein cyano hydrin minu'tes'longenitwas acidified with'l cc. of concentrated,

37 percent hydrochloric acid. The crude product was distilled underreduced pressure to obtain 2-chloroacrolein C.;-refractive index n-'1.4665; specific gravity 20/201.250. The molecular weight ofthe'product as determined bythe Menzies-Wright method was 116'ascompared with-a theoretical value of 117.5. chlorine and 11.3% nitrogenas compared with theoretical values of The yield and ExampleII.Reacti01z -0f hydrogen cyanide with crude 2-chl0r0acrolein A solutionof 114 grams of 97 percent acrolein (2' moles) in 228 grams of benzenewas chlorinated at 0 C.

While 2 liters of 3-dichloropropionaldehyde solution was fedtheretoo-ver a' period of an hour. The top layer (oil) ofthedistillateWascon'tinually rem'oved -while the' lower layer waszreturned as reflux.The distillation was 'continuedfor 15 minutes to remove all of thesteam-distillable oil from the system. The oil layer of the distillateWeighed 319 grams and by analysis with hydroxylamine was found tocontain 35.7 percent of 2-chloroacrolein. These results corresponded toa 63 percent yield and efliciency to crude 2- chloroacrolein solution.

A mixture of 0.4 gram of potassium cyanide catalyst (.006 equivalent)and 37 grams of hydrogen cyanide (1.38 moles, 10% excess) was stirred at15 C.18 C. while the 319 grams of 35.7 percent 2-chloroacrolein solutionwere added over a period of 45 minutes. Since very little heat wasevolved, 0.4 gram more of potassium cyanide catalyst (.006 equivalent)were added all at once. An exothermic reaction immediately began imumtemperature was held at 35 C. by strong cooling. After the mixture wasstirred at 10 C. to 20 C. for 30 minutes, it was acidified With 1 cc. ofchloric acid. The crude product was distilled under reduced pressure toobtain Z-chloroacrolein cyanohydrin with 78 percent yield and efiiciencybased on the crude 2- chloroacrolein.

7 Example III.Preparation of ethyl 3-chlo-ro-2-hydroxy- 3-butenoatemolecule and hence they 'are and the maxconcentrated hydro-- hours, itwas cooled to 25 C. and filtered to remove ammonium chloride.

The filtrate was fractionated to obtain ethyl 3-chloro-2-hydroxy-butenoate having the following properties: boiling point 63 C./3mm.; refractive index n -1.4530; specific gravity at 20 C./20 C.-1.202;molecular weight observed by the Menzies-Wright method-159.8 (theory164.5). Analysis showed the product to contain 21.9% chlorine, 43.3%carbon and 5.7% hydrogen, as compared with theoretical values of 21.6%chlorine, 43.8% carbon and 5.5% hydrogen. The compound was furtheridentified as ethyl 3-chloro-2-hydroxy-3-butenoate (rather than anisomer) by investigation of its infra-red and ultra-violet absorptioncharacteristics.

Example 1V.-Copolymerizati0n of ethyl-.i-chloro-Z-hydroxy-3-butenoateand acrylonitrile A Pyrex tube was charged with 3.0 grams of ethyl-3-chloro-2-hydroxy-3-butenoate, 7.0 grams of acrylonitrile, 10.0 ml. ofacetone, and .25 ml. of a 25% solution of diacetyl peroxide in dimethylphthalate. The gas phase was flushed with nitrogen, and the tube wasthen chilled in solid carbon dioxide and sealed, after which it wasplaced in a water bath maintained at 50 C. and rocked gently for 21hours. At the end of this period the tube was again chilled and brokenopen. The polymer was recovered by precipitation in isopropanol,filtered, and dried overnight in an air oven at 55 C. to 60 C. Thepolymer yield was 2.5 grams (25% conversion). It had a reduced viscosityof 0.28 in dimethylformamide at 30 C. and analyzed 73%polyacrylonitrile.

The copolymer is soluble in solvents, such as dimethylformamide, fromwhich strong and flexible fibers, films and coatings can be prepared.Such copolymers have improved flame-resistance, anti-static properties,and adhesive qualities, contributed in the first instance, by theirchlorine content, and in the other two instances by their hydroxylcontent.

As compared to the non-chlorine containing ester, ethyl2'hydroxy-3-butenoate, the chloro ester of this invention copolymerizeswith acrylonitrile at a rate which is about twice as fast, and theresulting copolymers have a higher molecular weight. The following tablepresents data on comparative polymerizations, carried out under the sameconditions given above:

AGRYLONITRILE COPOLYMERIZATIONS Percent Percent Relative 1 ReducedAcryloni- Acryloni- Rate of Viscosity in (lo-Monomer trile in trile inCopoly- Dirnethyl- Monomers Copolymer merization tormamlde Charged Ethyl3-Chlorohydroxy-3- butenoate 70. 0 73.1 1. Z 0. 28 D0 30. 0 51.. 8 2. 5Ethyl 2-hydroxy-3- butenoate 70. 0 85. 3 2. 5 Do 3D. 0 65. 8 4. 5 0. 09

Acryloniti-ile is the component having the faster rate ofpolymerization.

Example V.-C0p0 lymerizati0n of ethyl-3-chlor0-2-hydroxy-S-butenoate andstyrene Using the procedure of Example IV a tube was charged with 3.0grams of ethyl-3-chloro-2-hydroxy-3-butenoate, 7.0 grams of styrene,10.0 ml. of benzene, and .25 ml. of a 25% solution of diacetyl'peroxide.After 28.5 hours at C. the polymer yield was 1.3 grams (13% conversion).The polymer had a reduced viscosity of 0.13 in benzene at 30 C. andanalyzed 5.6% of the butenoate, by chlorine analysis.

The copolymer is useful in forming films from benzene solutions whichhave improved anti-static properties.

What is claimed is:

As a new composition of matter, ethyl 3-chloro-2-hydroxy-3-butenoate.

References Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES Lespieau: 6 Chem. Abst., p. 620 (1912). Stitz: 4 Chem. Abst.,pp. 7226-7 (1950). Gudgeon et al.: 46 Chem. Abst., p. 880 (1952).

